US5629982AExpiredUtility

Simultaneous electronic transactions with visible trusted parties

92
Priority: Mar 21, 1995Filed: Aug 20, 1996Granted: May 13, 1997
Est. expiryMar 21, 2015(expired)· nominal 20-yr term from priority
Inventors:Silvio Micali
G06Q 20/401H04L 51/23H04L 2209/56G06Q 20/40975G06Q 20/02G06F 2211/009H04L 63/0823G06F 2211/008H04L 9/0841G06Q 20/3825G06Q 20/00H04L 9/3247H04L 2463/102G06Q 50/188H04L 9/085H04L 2209/60H04L 63/0428G07F 7/1008G06Q 20/388H04L 63/061H04L 9/321G06Q 20/389G06Q 20/341
92
PatentIndex Score
514
Cited by
89
References
35
Claims

Abstract

A number of electronic communications methods are described involving a first and a second party (i.e., sender and recipient), with assistance from at least a trusted party, enabling electronic transactions in which the first party has a message for the second party. The first party, the second party and the trusted party undertake an exchange of transmissions, such that if all transmissions reach their destinations the second party only receives the message if the first party receives at least one receipt. Preferably, the identity of the first party is temporarily withheld from the second party during the transaction. At least one receipt received to the first party enables the first party to prove the content of the message received by the second party.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A method of transmitting a message using a trusted party, comprising the steps of: (a) a sender causing the trusted party to be provided with a version of the message that is encrypted in a key that is not available to the trusted party, and causing the trusted party to receive information identifying the sender and information identifying a recipient;   (b) the trusted party using the information identifying the recipient to cause information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender; and   (c) the trusted party causing a receipt for the message to be provided to the sender.   
     
     
       2. A method according to claim 1, wherein the message is intelligible to the recipient. 
     
     
       3. A method according to claim 1, wherein the trusted party is implemented using a tamper-proof device. 
     
     
       4. A method according to claim 2, wherein the message is encrypted with a key of the recipient. 
     
     
       5. A method according to claim 1, wherein the sender provides a proof that the sender causes the message to be provided to the recipient. 
     
     
       6. A method according to claim 5, wherein the proof includes a digital signature. 
     
     
       7. A method according to claim 5, wherein the proof is provided to the trusted party. 
     
     
       8. A method according to claim 7, wherein the trusted party provides a proof to the recipient. 
     
     
       9. A method, according to claim 1, wherein the receipt is provided by the recipient. 
     
     
       10. A method, according to claim 9, wherein the receipt proves the contents of the message. 
     
     
       11. A method, according to claims 10, wherein the receipt contains a digital signature of the recipient. 
     
     
       12. A method, according to claim 1 wherein the receipt proves the contents of the message. 
     
     
       13. A method of transmitting a message using a trusted party, comprising the steps of: (a) a sender causing the trusted party to be provided with an encrypted version of the message, information identifying the sender, and information identifying a recipient;   (b) the trusted party using the information identifying the recipient to cause information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender even if the recipient does not receive the message, or any version thereof, directly from the sender; and   (c) the trusted party causing a receipt for the message to be provided to the sender.   
     
     
       14. A method according to claim 13, wherein the encrypted version of the message is unintelligible to the trusted party. 
     
     
       15. A method according to claim 13, wherein the trusted party is implemented using a tamper-proof device. 
     
     
       16. A method according to claim 13, wherein the message is encrypted with a key of the recipient. 
     
     
       17. A method according to claim 13, wherein the sender provides a proof that the sender caused the message to be provided to the recipient. 
     
     
       18. A method according to claim 17, wherein the proof includes a digital signature. 
     
     
       19. A method according to claim 17, wherein the receipt is provided to the trusted party by the recipient. 
     
     
       20. A method, according to claim 19, wherein the receipt proves the contents of the message. 
     
     
       21. A method, according to claim 20, wherein the receipt contains a digital signature of the recipient. 
     
     
       22. A method of transmitting a message using a trusted party, comprising the steps of: (a) a sender causing the trusted party to be provided with a first encrypted version of the message;   (b) the trusted party causing a second encrypted version of the message to be provided to the recipient, wherein the second encrypted version of the message commits the contents of the message but is unintelligible to the recipient; and   (c) in response to the recipient providing an acknowledgement for receiving the second encrypted version of the message, the trusted party causing information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender and the trusted party causing the sender to receive a receipt for the message.   
     
     
       23. A method according to claim 22, wherein the first encrypted version of the message is unintelligible to the trusted party. 
     
     
       24. A method according to claim 22, wherein the second encrypted version of the message does not reveal the identity of the sender to the recipient. 
     
     
       25. A method according to claim 22, wherein the receipt includes the acknowledgement. 
     
     
       26. A method according to claim 22, wherein the receipt indicates that the recipient has been provided with the message. 
     
     
       27. A method according to claim 22, wherein the receipt proves the contents of the message. 
     
     
       28. A method according to claim 22, further comprising the step of: (d) in response to the trusted party not receiving the acknowledgement, having the trusted party cause the message to be provided to the recipient by alternative means.   
     
     
       29. A method according to claim 28, wherein the alternative means produces an alternative receipt for delivery of the message. 
     
     
       30. A method according to claim 22, wherein the acknowledgement commits the contents of the message. 
     
     
       31. A method according to claim 22, further comprising the steps of: (d) the trusted party requesting from the recipient a proof that the recipient has obtained an intelligible version of the message; and   (e) if the trusted party does not receive the proof, having the trusted party deliver the message by alternative means.   
     
     
       32. A method according to claim 31, wherein the alternative means produces an alternative receipt for delivery of the message. 
     
     
       33. A method according to claim 31, wherein the receipt includes the proof. 
     
     
       34. A method according to clam 31, wherein the receipt includes the alternative receipt. 
     
     
       35. A method according to claim 22, wherein the first encrypted version of the message is identical to the second encrypted version of the message.

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